Electronic devices, such as pagers, often incorporate communication between different semiconductor devices. In many electronic devices, the communication between semiconductor components involves data transference between a master device, e.g., a microprocessor, and a slave device, e.g., a support chip.
In conventional pagers, the slave device is capable of generating an external signal received by the master device which can cause an interrupt. Because the interrupt can be generated by many sources, rapid determination of a highest priority interrupt must be made by the master device. Under some circumstances, the determination of the highest priority interrupt may not be rapid enough to meet the needs of a system. Such a circumstance could arise, for example, when the slave device in a pager detects that a battery providing primary power has been removed from the pager, i.e., when the interrupt source is a "gone cell" interrupt. Subsequent to receiving the interrupt and ending communication, the master device normally shuts down the sections of the pager that draw high current, e.g., the receiver circuitry, and switches the power from the main battery to a backup battery. If too much time passes before the power is switched to the backup battery, the supply voltage could become low enough so that the memory of the pager is lost. This critical event would result in the loss of any messages that have been received by the pager.
Thus, what is needed is a more rapid method of data transference between the slave device and the master device.